Why does the Blue Nile flood more strongly than the White Nile?

The Blue Nile floods more strongly than the White Nile primarily due to the heavy summer monsoon rains that fall over the Ethiopian Plateau.21

While the White Nile provides a relatively steady, perennial flow throughout the year, the Blue Nile is characterized by a pronounced flood season from late July to October. This surge is driven by the rapid runoff from the Ethiopian highlands, where the river and its major tributaries—such as the Dinder and Rahad—originate.213

In contrast, the White Nile's flow is significantly more regulated. Its discharge is moderated by the large swamps and lagoons of the Al-Sudd region, which act as a natural buffer, and by the fact that its water sources are spread across the East African Plateau and the drainage of southwestern Ethiopia. During the peak of the flood season, the powerful surge of the Blue Nile is so significant that it actually holds back the White Nile at Khartoum, causing the latter to back up and form an extensive lake.214